Semiconductor structure

Abstract

A method of forming a semiconductor structure includes forming a conductive structure in a first dielectric layer. A second dielectric layer is formed over the first dielectric layer. A conductive contact is formed in the second dielectric layer. The second dielectric layer is etched to form a recess on a top surface of the conductive structure. A native oxide layer is formed on a top surface and a sidewall of the second dielectric layer, the top surface of the conductive structure, and a sidewall of the conductive contact. A first plasma process is performed to form a first material layer over the native oxide layer by using a first plasma gas. A second plasma process is performed to form a second material layer over the first material layer by a second plasma gas different from the first plasma gas. A spacer layer is formed on the second material layer.

What is claimed is: 
     
         1 . A semiconductor structure, comprising:
 a substrate;   a first dielectric layer over the substrate;   a conductive structure in the first dielectric layer;   a second dielectric layer over the first dielectric layer;   a conductive contact in the second dielectric layer, wherein a recess is between the conductive contact and the second dielectric layer;   a native oxide layer over a top surface and a sidewall of the second dielectric layer, a top surface of the conductive structure, and a sidewall of the conductive contact;   a first material layer over the native oxide layer and in the recess;   a second material layer over the first material layer and in the recess, wherein the second material layer comprises a material different from a material of the first material layer; and   a spacer filled in the recess.   
     
     
         2 . The semiconductor structure of  claim 1 , wherein the spacer is separated from the first material layer by the second material layer. 
     
     
         3 . The semiconductor structure of  claim 1 , wherein the second material layer is in contact with the first material layer. 
     
     
         4 . The semiconductor structure of  claim 1 , wherein the spacer is in contact with the second material layer. 
     
     
         5 . The semiconductor structure of  claim 1 , wherein the first material layer is a nitride layer and the second material layer is an oxide layer. 
     
     
         6 . The semiconductor structure of  claim 1 , wherein the material of the second material layer is different from a material of the spacer. 
     
     
         7 . The semiconductor structure of  claim 1 , wherein the native oxide layer has a first portion in contact with the conductive contact and a second portion in contact with the second dielectric layer, and wherein the first portion of the native oxide layer includes a material different from a material of the second portion of the native oxide layer. 
     
     
         8 . The semiconductor structure of  claim 7 , wherein the first material layer has a first portion in contact with the first portion of the native oxide layer and a second portion in contact with the second portion of the native oxide layer, and wherein the first portion of the first material layer includes a material different from a material of the second portion of the first material layer. 
     
     
         9 . The semiconductor structure of  claim 8 , wherein the second material layer has a first portion in contact with the first portion of the first material layer and a second portion in contact with the second portion of the first material layer, and wherein the first portion of the second material layer includes a material different from that of the second portion of the second material layer. 
     
     
         10 . The semiconductor structure of  claim 1 , wherein a top surface of the spacer is substantially coplanar with a top surface of the second material layer.